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This paper is the second of three papers stemming from a dual fuel Chrysler prototype engine which uses both diesel and gasoline direct injection running at near-stoichiometric conditions, as part of a project to explore the viability of incorporating an engine platform which utilizes low temperature combustion regimes into a modern automotive application. The combustion system was designed to tolerate high rates of EGR while maintaining combustion stability by using high charge motion intake port and a high energy ignition system. The engine ran on highly dilute SI combustion at low loads, Diesel Assisted Spark Ignition at medium loads and a transition to Diesel Micro Pilot ignition at medium to high load. The first paper explored the use of Diesel Assisted Spark Ignited at moderate loads 6.5 bar to 12.7 bar BMEP and the third paper to be published in 2024 will explore fuel property effects (mainly Cetane and Octane) through the use of alternative fuels.

This paper is the first of three papers stemming from a dual fuel Chrysler prototype engine which uses both diesel and gasoline direct injection running at stoichiometric conditions, as part of a project to explore the viability of incorporating an engine platform which utilizes low temperature combustion regimes into a modern automotive application. The combustion system used high rates of EGR while maintaining combustion stability by using high charge motion intake port and a high energy ignition system. The engine ran highly dilute SI combustion at low loads, Diesel Assisted Spark Ignition at medium loads and a transition to Diesel Micro Pilot ignition at medium to high load. This paper explores diesel assisted spark ignited combustion at medium loads 6.5 bar to 12.7 bar BMEP.

A set of experiments has been performed which were aimed at quantifying the effects of specific intake port geometry changes on large-scale in-cylinder motions. Using a modular engine with replaceable intake port blocks, 3 different intake ports were used and results obtained at 3 crank angles: BDC, 90° before TDC of compression, and at TDC of compression. For each port, in-cylinder flows were quantified using a pulsed laser and high-speed imager. The resulting images were analyzed using a particle-tracking scheme. The results of the experiments indicate that there are significant differences among the flows produced by the ports, particularly at BDC. Nearer TDC, the differences among the flows diminish, but some differences in velocity and vorticity scale and distribution remain. Tumble ratios are shown, using a variety of tumble ratio calculation methods.